/*t b c d
t current time   :nTime-sTime
b begining time  :curr
c chang in value :变化量end-curr
d duration       :持续时间 time */
/**
 * 
 * @param {Object} obj 元素对象
 * @param {Object} json 多个属性
 * @param {Object} time 变化时间
 * @param {Object} prop 运动函数
 * @param {Object} callback 回调函数
 */
//时间版本

function animateTime(obj,json,time,prop,callback){
	//一般定时器结束后最好清除
	clearInterval(obj.timer);
	var curr = {};
	var end = {};
	//通过for in 在上车前把所有东西装到包里
	for(var attr in json){
		if(attr == "opacity"){//opacity特殊东西特殊对待
			curr[attr] = getStyle(obj,attr)*100;//化为整数好计算
		}else{
			curr[attr] = parseInt(getStyle(obj,attr))||0;
		}
		end[attr] = json[attr];
		
	}
	
	
	//如果没写默认值 默认就是0 不然在IE出问题
	//var curr = parseInt(getStyle(obj,attr))||0;
	//var end = target;
	var sTime = new Date();//开始时间T0
	//开始变换了
	obj.timer = setInterval(function(){
		var nTime = new Date();//当前时间Tt
		var t = nTime -sTime;
		var d = time;
		//St = (Tt-T0)/Time*(S-S0)+S0
		//(nTime-sTime)/time 比例最多为1
		/*var prop = (nTime-sTime)/time; */
		if(t >=d){
			t = d;
			clearInterval(obj.timer);
			callback && callback.call(obj);
		}
		for(var attr in json){
			var b = curr[attr];
			var c = end[attr] - b;
			if(attr == "opacity"){
				//var s = prop*(end[attr]-curr[attr])+curr[attr];
				var s = Tween[prop](t,b,c,d);
				obj.style[attr] = s/100;
				obj.style.filter = "alpha(opacity="+s+")";
			}else{
				//var s = prop*(end[attr]-curr[attr])+curr[attr];
				var s = Tween[prop](t,b,c,d);
				obj.style[attr] = s+"px";
			}

		}

		
	},13);
	var Tween = {
        linear: function (t, b, c, d){  //匀速
            return c*t/d + b;   //  t/d = prop;
        },
        easeIn: function(t, b, c, d){  //加速曲线
            return c*(t/=d)*t + b;
        },
        easeOut: function(t, b, c, d){  //减速曲线
            return -c *(t/=d)*(t-2) + b;
        },
        easeBoth: function(t, b, c, d){  //加速减速曲线
            if ((t/=d/2) < 1) {
                return c/2*t*t + b;
            }
            return -c/2 * ((--t)*(t-2) - 1) + b;
        },
        easeInStrong: function(t, b, c, d){  //加加速曲线
            return c*(t/=d)*t*t*t + b;
        },
        easeOutStrong: function(t, b, c, d){  //减减速曲线
            return -c * ((t=t/d-1)*t*t*t - 1) + b;
        },
        easeBothStrong: function(t, b, c, d){  //加加速减减速曲线
            if ((t/=d/2) < 1) {
                return c/2*t*t*t*t + b;
            }
            return -c/2 * ((t-=2)*t*t*t - 2) + b;
        },
        elasticIn: function(t, b, c, d, a, p){  //正弦衰减曲线（弹动渐入）
            if (t === 0) {
                return b;
            }
            if ( (t /= d) == 1 ) {
                return b+c;
            }
            if (!p) {
                p=d*0.3;
            }
            if (!a || a < Math.abs(c)) {
                a = c;
                var s = p/4;
            } else {
                var s = p/(2*Math.PI) * Math.asin (c/a);
            }
            return -(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) + b;
        },
        elasticOut: function(t, b, c, d, a, p){    //正弦增强曲线（弹动渐出）
            if (t === 0) {
                return b;
            }
            if ( (t /= d) == 1 ) {
                return b+c;
            }
            if (!p) {
                p=d*0.3;
            }
            if (!a || a < Math.abs(c)) {
                a = c;
                var s = p / 4;
            } else {
                var s = p/(2*Math.PI) * Math.asin (c/a);
            }
            return a*Math.pow(2,-10*t) * Math.sin( (t*d-s)*(2*Math.PI)/p ) + c + b;
        },
        elasticBoth: function(t, b, c, d, a, p){
            if (t === 0) {
                return b;
            }
            if ( (t /= d/2) == 2 ) {
                return b+c;
            }
            if (!p) {
                p = d*(0.3*1.5);
            }
            if ( !a || a < Math.abs(c) ) {
                a = c;
                var s = p/4;
            }
            else {
                var s = p/(2*Math.PI) * Math.asin (c/a);
            }
            if (t < 1) {
                return - 0.5*(a*Math.pow(2,10*(t-=1)) *
                        Math.sin( (t*d-s)*(2*Math.PI)/p )) + b;
            }
            return a*Math.pow(2,-10*(t-=1)) *
                    Math.sin( (t*d-s)*(2*Math.PI)/p )*0.5 + c + b;
        },
        backIn: function(t, b, c, d, s){     //回退加速（回退渐入）
            if (typeof s == 'undefined') {
               s = 1.70158;
            }
            return c*(t/=d)*t*((s+1)*t - s) + b;
        },
        backOut: function(t, b, c, d, s){
            if (typeof s == 'undefined') {
                s = 3.70158;  //回缩的距离
            }
            return c*((t=t/d-1)*t*((s+1)*t + s) + 1) + b;
        },
        backBoth: function(t, b, c, d, s){
            if (typeof s == 'undefined') {
                s = 1.70158;
            }
            if ((t /= d/2 ) < 1) {
                return c/2*(t*t*(((s*=(1.525))+1)*t - s)) + b;
            }
            return c/2*((t-=2)*t*(((s*=(1.525))+1)*t + s) + 2) + b;
        },
        bounceIn: function(t, b, c, d){    //弹球减振（弹球渐出）
            return c - Tween['bounceOut'](d-t, 0, c, d) + b;
        },
        bounceOut: function(t, b, c, d){
            if ((t/=d) < (1/2.75)) {
                return c*(7.5625*t*t) + b;
            } else if (t < (2/2.75)) {
                return c*(7.5625*(t-=(1.5/2.75))*t + 0.75) + b;
            } else if (t < (2.5/2.75)) {
                return c*(7.5625*(t-=(2.25/2.75))*t + 0.9375) + b;
            }
            return c*(7.5625*(t-=(2.625/2.75))*t + 0.984375) + b;
        },
        bounceBoth: function(t, b, c, d){
            if (t < d/2) {
                return Tween['bounceIn'](t*2, 0, c, d) * 0.5 + b;
            }
            return Tween['bounceOut'](t*2-d, 0, c, d) * 0.5 + c*0.5 + b;
            }
    };
    console.log("时间版");
 }

//速度版本
function animateSpeed(obj,json,callback){
    console.log("速度版");
    clearInterval(obj.timer);
    obj.timer = setInterval(function(){
        var mark = true;
        for(var attr in json){
            var cur = null;
            if(attr == "opacity"){
                cur = getStyle(obj,attr)*100;
            }else{
                //如果没写 默认填充成0
                cur = parseInt(getStyle(obj,attr))||0;
            }
            var target = json[attr];
            var speed = (target - cur)*0.2;
            speed = speed>0?Math.ceil(speed):Math.floor(speed);
            if(cur != target){
                if(attr == "opacity"){
                    //IE opacity兼容问题
                    obj.style.filter = "alpha(opacity="+(cur+speed)+")";
                    obj.style[attr] = (cur + speed)/100;
                }else{
                    obj.style[attr] = cur + speed + "px";
                }
                mark = false;

            };
        }
        if(mark){
            clearInterval(obj.timer);
            callback && callback.call(obj);
        }
    },1000/30);

}
function getStyle(obj,attr){
    return getComputedStyle(obj)[attr]?getComputedStyle(obj)[attr]:obj.currentStyle[attr];
}
exports.animateSpeed = animateSpeed;
exports.animateTime = animateTime;


